Question

I can’t quite figure this one out. To make it simple I’ll explain what I’m trying to do.

Currently, I am working on a nHibernate project which uses a repository pattern. Inside the database are a bunch of tables that have “Description” fields. Now, I am trying to localize these tables to use a common “Resource” table.

So, I have these 2 tables:

Table 1 – Resources :
ResourceId, LanguageId, Value

Table 2 – LinkLabels :
LinkLabelId, Description, ResourceId

Then there is a session token that contains a “LanguageId” which is the preferred language of the user.

Okay, with that said, what I need to do is get the “Value” from the ResourcesTable where ResourceId from LinkLabels = ResourceId from Resources for objects that have a “ResourceId”. But I’ve got to do this with a Generic type.

Here is what I have so far:

public IQueryable<T> ToQueryable<T>()
{
    try
    {
        PropertyInfo resourceProperty = typeof(T).GetProperty("ResourceKey");

        if (resourceProperty != null)
        {
            // Somthing like this, but of course this won't work
            // because x.ResourceId doesn't exist because of generic, and the select
            // statement is invalue.
            //
            // return from x in this.session.Query<T>()
            //        join p in this.session.Query<Resource>() on x.ResourceId equals p.ResourceId
            //        where p.LanguageId = 1 // this will be from a session object, hardcoded to 1 for now
            //        select x where x.Description is p.value;
        }
        else
        {
            return this.session.Query<T>();
        }
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

Answer 1

Create an interface like this:

interface IResource {
int ResourceId { get; set;}
}

Then use a constraint:

public IQueryable ToQueryable() where T: IResource
{
…
}

Then you have to make all your types implement IResource as well.